Thermionic amplifying apparatus



Jan. 11 1927. I 1,614,136

M. c. *A. LATOUR THERMIONIC AMPLIFYING APPARATUS Filed Nov. 2 9

Attorney.

Patented Jan. 11, 1927.

UNITED STATES v I 1,614,136 PATENT OFFICE.

MARIUS C. A. LATOUR, OF PARIS, FRANCE, ASSIGNOR TO LATOUR CORPORATION, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE.

THERMIONIC AMPLIFYING APPARATUS.

Application filed November 2, ISIS/Serial No. 260,909, and in France December 20, 1916.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921. 41 STAT. I, 1313.)

The object of the invention is to provide thermionic tube amplifiers constructed in the manner set forth in my Patent No. 1,405,523, granted February 7 1922, and particularly suitable for the purpose of amphfying current of a specified frequency.

Such amplifiers are advantageous when it is desired ,to suppress currents of atmospherical origin in wireless receivers, or else when it is desired to amplify a reception of specified pitch.

In accordance with a theory commonly admitted, atmospheric currents are mainly due to excitations by shock of the receiving antenna, givin rise to oscillations having the natural period of the antenna; and consequently having in the-ordinary methods of reception the very period of the oscillations that are being received. According to the invention, the period of the oscillations due to the currents of atmospherical origin may be differentiated from the period of the oscillations that it is desired to receive by tuning the antenna circuit to a frequency different from that of the oscillations to be received, and subsequently reinforcing by means of one or more thermionic tubes the reception thus weakened, without reinforcing the interfering oscillations.

This result is arrived at by utilizing in the thermionic tube amplifiers high frequency iron-cored transformers as proposed in my above mentioned patent and by constructing them in such a way that they take a large magnetizing current (few actual turns with an air gap or a multiplicity of air gaps in the magnetic circuit to increase the reluctance thereof) at the frequency corresponding to the wave length in qu stion, and by branching across their terminals a capacity,

which at this frequency absorbs a leading wattless current equal to the lagging magnetizing current of the transformer.

There'is thus obtained the condition of resonance which gives the maximum am plification for the given frequency. Since the condition of resonance does not exist for all other wave lengths. the received currents corresponding to the latter are not amplified to the same extent.

What has just been said is also applicable to low-frequency amplification when it is desired to amplify received currents of musithe common battery 5.

cal note frequency. It is accordingly possible by arranging suitable capacities at the termlnals of the primaries or secondaries of the low frequency transformers (constructed to absorb a large ma netizing current) to amplify more particu arly received currents of musical note frequency.

In a high and low frequency amplifier, therefore, it is possible to provide for the selection by wave length on the hi 'h-frequency amplification, and for selection by musical note frequency on the-low-frequency amplification.

In the accompanying drawings:

Figure 1 shows a type of the magnetic circuit of the transformer.

Figure 2 gives a diagram of an amplifier for high-frequency current.

Figure 3 is a diagram of an amplifier for low-frequency current.

Fig. 1 shows by way of example one of the forms that might. be adopted for the transformer. .As described in my Patent N0.1,405,523, the primary winding may consist of a coil Y sandwiched between the coils X and Z which are connected in series and constitute the secondary winding, or conversely X and Z may be the primary and Y the secondary. This arrangement greatly reduces magnetic leakage between the primary and secondary, or, in other words, gives close electromagnetic coupling. In accordance with the present invention the magnetic circuit is made to include an adjustable gap or a plurality of gaps occupied by air or other non-magnetic materiaL. In .Fig. 1, reference character E represents byway of example three such air gaps.

Figure 2 shows an amplifier with four thermionic tubes, 1, 2, 3, 4. Each of these thermionic tubes comprises a plate, a grid and a filament. The filaments are heated by The required potential difference between the filaments and the plate is supplied by the battery 6.

The antenna current which it is desired to amplify is led to the terminals 13 and 14 and is amplified by the tubes 1, 2, 3, and 4 successively, to which it is led through the air-gap transformers 7, Sand 9. Upon the secondaries of these transformers capacities 15,16 and 17 are utilized, which are adjusted so that each of the circuits may. be tq'qgaddto the wave length that is to be am- 1 e "Finally the last tube 4-detects the current, due to the capacity 11 shunted by a resist- 'ance inserted in series .with its grid, and the received current reaches the receiver 10 placed on the secondary of a telephone transformer 12.

Figure 3 shows the amplification of a current of low fre uency, and con uently possessing a spec ed musical pitch. n this figure the same letters represent the same elements as in Figure 2 and the telephone transformer in also tuned.

The low-frequency current,'instead of arriving directly between the grid and the filament of the first tube, is led thereto through the transformer I.

As 1n the case of Fi ure 2, capacities 15' 16 and 17 are provide but they are tuned to the frequency of the current or specified periodicity to be reinforced. v

What I claim as new, and desire to secure by'Letters Patent of the United States, is:

1. Amplifying apparatus for radio and the like signals, comprising a thermionic tube containing filament, grid and plate members, and a magnetic-cored transformer with a plurality of air gaps in its magnetic circuit to increase the reluctance thereof, said transformer havin its primary winding adapted to receive t e current to be amplified and its secondary winding connected to the grid circuit of the thermionic tube, said transformer being adapted, by capacity adjunction, to form a resonant unit for a specified frequency.

2. Amplifying apparatus for radio and the like signals, comprising a thermionic tube containing filament, grid and plate members, and a magnetic-cored transformer with an air gap in its magnetic circuit to increase the reluctance thereof, said transformer having its primary winding adapted to receive the current to be amplified and its secondary winding connected to the grid circuit of the thermionic tube, said transformer being adapted, bycapacity adjunction, to form a resonant unit for a specified frequency.

3. Amplifying apparatus for radio and the like signals, comprising a thermionic tube containing filament, grid and plate members and a magnetic-cored transformer with a variable air gap in its magnetic circuit to vary the reluctance thereof, said transformer having its primary winding adapted to receive t e current to be amplified and its secondary winding connected to the grid circuit of the thermionic tube, said transformer being adapted, by capacity adjunction, to form a resonant unit for a specified frequency.

4. In a thermionic amplifier for radiorgrmae telegraphic and similar signals, the combiamplified and its secondary winding connected to the grid circuit of a thermionic tube, said transformer being adapted, by capacity adjunction, to form a resonant unit 503 the frequency of the current to be ampli- 5. In a thermionic amplifier for radio-telegraphic and siinilar si als, the combination with a wave collecting circuit tuned to a frequency slightly different from that of the oscillations to be amplified, of a magnetic-cored transformer with an air gap in its magnetic circuit to increase the reluctance thereof, having its primary winding adapted to receive the current to be amplified and its secondary winding connected to the'grid circuit of a thermionic tube, said transformer being adapted, by capacity adjunction, to form a'resonant unit for the frequency of the current to be amplified.

6.. In a thermionic. amplifier for radiotelegraphic and similar signals, the combination with a wave collecting circuit tuned to a frequency slightly different from that of the oscillations to be amplified, of a ma'gnetic-cored transformer, com rising an air gap, said air gap being variable so as to permit of tuning in accordance-with the oscillations to be amplified, and an amplifyin tube the grid circuit of which is connectei to the said magnetic-cored transformer.

7 Apparatus for radio and like signals, comprising a plurality of thermionic tubes each containing filament, grid and plate electrodes, circuits including said electrodes,

a high-frequency transformer coupling-the circuits of adjacent thermionic tubes in cascade, said transformer comprising separate primary and secondar windings, the cir-' cuits of said windings eing closely coupled electromagnetically, and a ca acity connected across at least one of said windings to compensate for the ma netizing current of the transformer, where y said transformer as a whole and said capacity constitute a single resonant unit.

8. Amplifying app aratus for radio and Ill! Ill

like signals, COIDEIlSlIlg a plurality of thermionic tubes cac containing filament, grid and plate electrodes, circuits includin said electrodes, a high-frequency trans ormer coupling circuits of said thermionic tubes in cascade, said transformer comprising separate primary and secondary windings together with a core of magnetic material, the circuits of said windings being closelyicoupled electromagnetically, and a capacity connected across at least one of said windings .to compensate for the magnetizing current of the transformer, whereby said transformer as a whole and said capacity constitute a single resonant unit.

9. Amplifying apparatus for radio and like signals, comprising a plurality of thermionic tubes each having filament, plate and grid electrodes, circuits including said electrodes, a high-frequency transformer coupling circuits of adjacent thermionic tubes in cascade, said transformer comprising separate primary and secondary windings, the circuits of said windings being closely coupled electromagnetically, and a capacity connected across at least one of said windings and arranged to constitute a single resonant unit with said transformer as a whole.

10. Amplifying apparatus for. radio and like signals, comprising a lurality of thermionic tubes each having filament, plate and grid elctrodes, circuits including said electrodes, a high-frequency transformer coupling circuits of adjacent thermionic tubes in cascade, said transformer comprising separate primary and secondary windings to gether with a core of magnetic material, the circuits of said windings being closely coupled electromagnetically,and a capacity connected across at least one 'of said windings and arranged to constitute a single resonant unit with said transformer as a whole.

11. Am lifying apparatus for radio and like signa s, comprising a plurality of thermionic tubes each having filament, plate and grid electrodes, circuits including said electrodes, a high-frequency transformer coupling circuits of adjacent thermionic tubes in cascade, said transformer comprising separate primary and secondary windings, the

circuits of said windings being closely coupled electromagnetically, a capacity connected across at least one of said windings and arranged to constitute a single resonant unit with said transformer as a whole, and adjustable means for tuning said resonant upifg tcp the frequency of the current to be ampi e 12. In a signaling system, a detecting device for changin the frequency of an incoming signal. a plurality of amplifying devices coupled to said detecting oevice by resonant units, each unit including a magnetic-cored transformer having an air gap, and a capacity across each transformer whereby each unit is resonant to a specified frequency.

In testimony whereof I afiix my si nature.

MARIUS o. A. LAToUR. 

